Operating mechanism for throttle-valves



(No Model.) 2 Sheets-Sheet 1.

K. RUSHTON. OPERATING MECHANISM FOR THROTTLE VALVES.

No. 555,738. Patnted M5123, 1895.

FIQJ, F

I nventor' Wit 7665565 lferuzet/v .Zluskicm M 5 M W (No Modei.) 2Sheizs-Sheet 2.

K.RUSHTON.; OPERATING MECHANISM FOR THROTTLE VALVES.

No. 555,738. Patented Mar-Q 3, 1896.

AMBREW BGIAH M PHOID-UMQWASMINEWREE.

lJNrE STATES KENNETH RUSIITON, OF PHILADELPHIA, PENNSYLVANIA OPERATINGMECHANISM FOR THROTTLE-VALVES.

SPECIFICATION forming part of Letters Patent No. 555,738, dated March 3,1896.

Application filed July 31, 1895. Serial No. 557,788. (No model.)

To aZZ whom, it may concern.-

Be it known that I, KENNETH RUsH'rON, a citizen of the United States,residing in Philadelphia, Pennsylvania, have invented certainImprovements in Operating Mechanism for 'lhrottle-Valves, of which thefollowing is a specification.

The object of my invention is to so construct lever mechanism foroperating throttle-valves under pressure that the leverage exerted willbe greater in starting the movement of the valve than in continuing themovement, whereby when the valve is subjected to pressure the power isexerted most advantageously, while when the valve has been partly liftedand the pressure upon the same reduced or equalized the decreasedleverage provides for a quicker movement of the valve than in startingto open it.

A further object of my invention is to hold the valve in the closedposition by means of the lever mechanism.

In the accompanying drawings, Figure 1 is a view partly in section ofthe throttle valve illustrating my invention, showing the valve closed.Fig. 2 is a view of the lever mechanism, showing the valve-stem raisedpart way. Fig. 3 is a view showing the valvestem raised the full height.Figs. 4 and 5 are views illustrating modifications of the invention,which illustrate a rocking motion. Figs. (5 and 7 are views showingchangeable fulcrums of the lever, the lever being shown in.mid-position.

In Fig. 1, A represents the ordinary throttle-valve casing, which isadapted to a locomotive and through which the steam passes from theboiler.

B is the valve having two disks Z) Z) adapted to valve-sears a a on thecasing, the pressure being external, as shown by arrows, and the excesspressure being downward,owing to the difference in area of thevalvedisks b b. Secured to the valve is a \alvestem 13', having a head13 in which are slots 0 c, and adapted to these slots are pins d d,mounted on one arm of a lever D fulcrumed at 61- the lever D beingconnected to an opcrating-rod D at d.

Then the valve is in the position shown in Fig. 1, the pin 61 is in theupper'portion of the slot 0 and the pin (1 is in the lower part of theslot 0 and rests against the bottom of the slot, holding the valveclosed.

The first movement of the lever D in the direction of its arrow, Fig. 1,will be to elevate the valve-stem I)" and its valve through the mediumof the pin (1, being represented by the lines X Y. Consequently withthis leverage the valve can be readily lifted off its seat against thepressure; but as soon as the lever reaches the position shown in Fig. 2the pin (1 has reached the upper end of its slot. Consequently it actson the valve-rod, the leverage being then that represented by the linesX. Z. Hence the valve is raised quickly with little exertion, as thepressure on the valve is equalized. Thus, while the movement in startingis comparatively slow, said movement is easy, owing to the advantageousleverage, while when the leverage is decreased the force to be overcomeis also decreased as the pressure upon the valve is decreased orequalized. IIence rapid movement of the same is possible without undueeffort.

Instead of shifting the bearing of the lever upon the valve-stern fromone pin to another, as shown in Figs. 1, 2 and 3, I may substitutetherefor a modified form of shifting bearing consisting of a curved headB againstwhich the upper portion of the lever D bears, and as the levermoves in the direction of the arrow, Fig. 4, the leverage will begradually decreased from X Y to X Z as the valve is raised. Consequentlyinstead of an abrupt shifting of the hearing, as in Fig. 1, a gradualshifting of the same and a gradually-increasing movement of the valvewill take place.

In Fig. 6 I have shown the lever as provided with a shifting bearingupon its fixed support instead of upon the valve-stem, said bearingbeing the two pinsff adapted to slots 9 g, and in Fig. 7 I have shown arocking bearing B of the lever upon the fixed support. Itwill beevident, therefore, that the object of my invention is attained by theshifting bearing of the lever, whether that shifting bearing be thebearing of the lever on the valve-stem or on the fixed support.

I claim as my invention 1. The combination of a throttle valve closed bypressure, with an operating-lever having a shifting bearing, whereby theleverage exerted is greater in starting to open the valve, than afterthe movement has been started, the valve-rod being connected to thelever, whereby no movement of the valverod, when the valve is closed, ispossible without corresponding movement of the lever, substantially asdescribed.

2. The combination of the casing, the valve therefor closed underpressure, its stem, a head on said stem, a pivoted lever having a fixedfulcrum and a movable connection with the head, the first movement ofthe lever being to raise the valve slowly against the pressure, themovement of the valve being increased owing to the change of leverage,substantially as described.

3. The combination of a throttle valve closed by pressure with anoperating-lever having a shifting bearing, whereby the leverage exertedis greater in starting to open the valve, than after the movement hasbeen started, said lever being so coupled to the rod as to hold it inits closed position, sub stantially as described.

4. The combination of the valve-casing, the valve, its stem, the head onthe stem, two slots in the head, a lever having a fixed fulcrum andhaving projections adapted to the slots, each projection having acertain amount of lost motion Within the slots and so arranged that theprojection nearest the fulcrum will act first to move the valve off itsseat and the second projection will act to open the valve, substantiallyas described.

In testimony whereof I have signed my name to this specification in thepresence of two subscribing witnesses.

KENNETH RUSHTON.

Witnesses:

HENRY HoWsoN, WILL. A. BARR.

